There have long been various chemical processes for producing gasoline and other fuels. A problem with these prior processes has been that they either fail to produce high octane gasoline, or they fail to do so efficiently.
These prior processes include that of Harandi, U.S. Pat. No. 5,171,912, issued on Dec. 15, 1992. Harandi discloses a process for the production of C+ gasoline from n-butane and propane. The Harandi process includes the steps of contacting a fresh feedstream including normal butane with shape selective medium pore zeolite catalyst particles under conditions sufficient to convert n-butane to an effluent stream including C+ alkanes; separating the effluent stream in a fractionator to recover an overhead stream including propane; contacting the propane stream and a fresh propane feedstream with shape selective, medium pore zeolite catalyst particles under conversion conditions sufficient to convert propane to a mixture including C+ alkanes; deethanizing the mixture and passing the deethanized product including C+ alkanes to the fractionator for separation concurrent with the effluent stream; recovering a bottom stream including C+ gasoline from the fractionator; preferably, distilling an intermediate stream including C alkanes from the fractionator and recovering a stream including isobutane and a stream including unconverted normal butane; and recycling the unconverted normal butane to the normal butane feedstream to the integrated process.
Ward, et al., U.S. Pat. No. 4,393,259, issued on Jul. 12, 1983, reveals a process for converting propane or butane to gasoline. The Ward, et al. process includes the steps of passing feed hydrocarbon into a dehydrogenation zone; passing the entire dehydrogenation zone effluent including hydrogen and light by-products into a catalytic condensation zone where the resulting olefins are converted into dimers and trimers; passing the condensation zone effluent stream into a separation zone in which the dimers and trimers are concentrated into a product stream, with unconverted feed hydrocarbon and hydrogen being recycled to the dehydrogenation zone.
Vora, et al., U.S. Pat. No. 4,304,948, issued on Dec. 8, 1981, teaches a multi-step hydrocarbon conversion process for converting butane to gasoline. The process includes the steps of passing butane into a dehydrogenation zone and the entire dehydrogenation zone effluent is then passed into a catalytic condensation zone where butylene is converted into C and C hydrocarbons; commingling and separating the condensation zone effluent, a stripper overhead stream and an absorber bottoms stream into vapor and liquid portions; passing the liquid into the stripper and contacting the vapor portion with stripper bottoms liquid in an absorber; contacting the absorber overhead stream with liquid butane in a second absorber to remove C hydrocarbons and recycling the dehydrogenation zone; and debutanizing a portion of the stripper bottoms to yield the liquid butane and a gasoline product.
Capsuto, et al., U.S. Pat. No. 4,444,988, issued on Apr. 24, 1984, discloses the use of liquefied propane and butane or butane recycled to control the heat of reaction of converting olefins to gasoline and distillate. The Capsuto, et al. process uses beds and separates the effluent product from the beds into a gas in a liquid phase, cools the gas phase to form additional liquid and heat exchanges the liquid with the overhead gas from the separator.
Wilson, U.S. Pat. No. 5,093,533, issued on Mar. 3, 1992, reveals blended gasolines and a process for making the blended gasolines. The Wilson process involves mixing of a butane-pentane rich component, and natural gasoline component, and at least one octane-enhancing component. The mix is weathered during the blending operation to remove light-weight hydrocarbons including two, three and four-carbon components.
Hiles, et al., U.S. Pat. No. 5,310,954, issued on May 10, 1994, discloses a process for preparing tetrahydrofuran. The Hiles et al. process separates tetrahydrofuran from a feed mixture containing water, lower alkanol and tetrahydrofuran, which includes distilling the mixture in a first distillation zone at a first pressure; recovering from an upper part of the distillation zone a first vaporous mixture including water, lower alkanol and tetrahydrofuran; subjecting the material from the first vaporous mixture to condensation conditions in a condensation zone; passing condensate from the condensation zone to a second distillation zone operated at a second pressure higher than the first pressure; recovering from an upper part of the second distillation zone a second vaporous mixture including water, lower alkanol and tetrahydrofuran that has a lower concentration of tetrahydrofuran than the first vaporous mixture; and recovering from a lower part of the second distillation zone a stream including substantially pure tetrahydrofuran.
It is thus an object of the present invention to provide a process of producing a very high octane alcohol product efficiently.
It is another object of the present invention to provide such a process which can be practiced with conventional heat exchanger and separator tank equipment.
It is still another object of the present invention to provide such a process which is safe to practice.
It is finally an object of the present invention to provide such a process which is inexpensive to practice.